1. Field of Invention
The present invention pertains generally to a device and method for adjustably attaching fins to a sportboard. The invention is particularly, but not exclusively, useful for attaching fins in a manner that allows for quick and convenient adjustment of the position of a fin on a sportboard to maximize the sportboard performance.
2. Description of Related Art
Sportboards, such as surfboard and sailboards, are well known in the prior art for providing recreational enjoyment. Typically, between one to four fins are attached to the underside of the board for facilitating stability and maneuverability. The fins have often been permanently mounted to the underside of the board.
However, there are several disadvantages to permanently mounting a fin to a board. Specifically, the fin cannot be easily removed and replaced if it becomes damaged. Further, the fin cannot be replaced with another fin having different performance properties. This would be advantageous if the user wishes to experiment with different fin configurations according to prevailing wind and surf conditions. Still further, a permanently mounted fin makes the surfboard unwieldy and difficult to transport. For the above reasons, it would be desirable to have fins that can be detachably mounted to the surfboard.
In addition to being detachable, it would be helpful to be able to adjust the position of a fin relative to the board when it is attached. In particular, to maximize the effectiveness of a fin for a variety of wind and surf conditions, it is important to be able to change the longitudinal position of the fin on the board. It is also desirable to be able to change the fin roll angle, i.e., the angle the fin makes with respect to the underside of the board. Additionally, it is important to be able to adjust the fin by hand or with a small tool which would fit within a swimming suit or a wetsuit pocket without causing any discomfort to the wearer.
U.S. Pat. No. 6,139,383, which issued to Barry A. Jolly et al for an invention entitled xe2x80x9cFin Assemblyxe2x80x9d, discloses a fin attachment system wherein a mounting device having a front socket and a rear socket is embedded within a surfboard. A fin having predetermined projections are respectively inserted into the front socket and rear socket and fixed thereto by set screws. For the device as disclosed by Jolly et al, however, there is no tag slot or pin slot in the socket mounting to permit longitudinal movement or adjustment of the fin roll angle.
U.S. Pat. No. 5,997,376, which issued to Block et al for an invention entitled xe2x80x9cSurfboard Fin Mounting Systemxe2x80x9d, discloses a fin that is adjustably attached to a box which is embedded within the surfboard. (The box is mounted in an opening cut into the surfboard.) The box includes a tag slot, but not a pin slot, and the fin is detachably fixed to the surfboard by passing a fastener through the top of the surfboard and threading the fastener into the fin. For the device disclosed by Block et al, however, the fin and tag lack versatility because they are a single integral unit. Further, the tag interfits within the tag slot in a manner which allows for longitudinal adjustment only. Additionally, it is undesirable to place an unsightly opening in the surfboard for installing a contrasting box which visibly extends through the surfboard.
U.S. Pat. No. 5,672,081, which issued to Whitty for an invention entitled xe2x80x9cSurf Fin Fixing Systemxe2x80x9d, discloses a detachable fin wherein two spaced-apart tabs extend downwardly from the fin. The tabs are inserted into slots within a fixing element which is embedded in the surfboard and fixed thereto by a set screw which is obliquely inserted into the fixing element until it contacts a tab. However, Whitty does not envision any structure for adjusting the fin longitudinal position or fin roll angle. The main emphasis of Whitty is simply to provide a fin removal system.
In the light of the above, it is an object of the present invention to provide a sportboard fin attachment system that allows for quick and easy attachment and removal of the fin from the board. It is another object of the present invention to provide a sportboard fin attachment system that allows for adjustment of both longitudinal fin position and fin roll angle relative to the board. Yet another object of the present invention is to provide a sportboard fin attachment system wherein the user can adjust the longitudinal fin position and fin roll angle by hand or with a small implement which can be comfortably stowed in a swimsuit or wetsuit. Still another object of the present invention is to provide a sportboard fin attachment assembly which is easy to install on a sportboard and has significant durability. Another object of the present invention is to provide a sportboard fin attachment system which is easy to manufacture in a cost efficient manner.
As used herein, the term xe2x80x9csportboardxe2x80x9d is intended to mean all types of boards used in water such as surfboards, wakeboards, sailboards and body boards. The term is also intended to encompass all types of water craft such as boats, kayaks, canoes and catamarans.
An alternative sportboard assembly comprises a sportboard with a with bilateral tag engagement unit and a tag fixed to a fin. The tag comprises first and second opposing surfaces and a tag-pin hole extending through the tag from the first to the second surface. A bilateral tag pin with a first and second end is disposed within the tag-pin hole. The first end protrudes beyond the first surface and the second end protrudes beyond the second surface. The tag is releasably secured to the bilateral tag engagement unit. The fin and tag are preferably integrally formed from a single member.
The sportboard has a longitudinal axis, and the tag-pin is about perpendicular to the longitudinal axis. The bilateral tag engagement unit has a first clamp for securing the first end of the tag-pin, and a second clamp for securing the second end of the tag-pin.
A first cap screw with a first threaded shaft controllably imparts a first force to the first clamp, and a second cap screw with a second threaded shaft controllably imparts a second force to the second clamp.
The bilateral tag engagement unit has a plug-base with first and second barrel guide holes respectively disposed beneath the first and second clamps. A first T-nut has a T-nut base disposed beneath the plug-base and a first threaded barrel attached to the base and extending through the first barrel guide hole. A second T-nut has a second T-nut base secured to a second threaded barrel. The second T-nut base is disposed below the plug base, and the second threaded barrel extends through the second barrel guide hole. The first and second threaded shafts of the cap screws are threadably engaged with the first and second threaded barrel respectively.
The first clamp is suspended between first and second flexible anti-torsion suspension members. The tension members exert a continual force on the first clamp, resulting in a lock washer effect on an engagement between the first threaded shaft and the first threaded barrel.
The first clamp comprises an elongated upper clamp member and an elongated lower clamp member separated by a pin slot. The upper and lower clamp members have a plurality of opposing ridges and grooves for engaging the first end of the tag-pin in a plurality of longitudinal positions. The first clamp can be slidably adjusted to any groove within the first pin slot. When the first securing member is engaged, the first tag pin becomes constrained in a predetermined groove within the first pin slot.
The second clamp comprises an elongated upper clamp member and an elongated lower clamp member separated by a pin slot. The upper and lower clamp members of the second clamp have a plurality of opposing ridges and grooves for engaging the second end of the tag-pin in a plurality of longitudinal positions. The second clamp can be slidably adjusted to any groove within the second pin slot. When the second securing member is secured, the first tag pin is secured in a predetermined groove within the first pin slot.
A center channel separates the first clamp from the second clamp. The center channel has a length and width sufficient for insertion of the tag in the center channel. The tag is tapered, and surfaces of the first and second clamp that face the center channel are tapered to snugly receive the tapered tag.
At least one pin slot intersects the center channel. The pin slot being sufficient size to allow passage of the tag-pin.
The tag engagement member includes a bilateral plug and a bilateral socket having a cavity into which the bilateral plug is fitted, and wherein the bilateral plug is a single contiguous member including the first clamp and the second clamp.
A method of releasably securing the fin to the sportboard comprises the followings steps: The first end of the tag-pin is inserted through the bore in the tag until the first end of the tag pin extends beyond the first side and the second end extends beyond the second side of the tag. The tag-pin is positioned above a select tag pin slot, and the tag is inserted into the center slot of the tag engagement member, thereby inserting the tag-pin through the select tag-pin slot and through the cross-slot pin guide. The tag is then slid longitudinally through the center slot of the tag engagement member, thereby sliding the first and second sides of the tag pin through the first and second pin slots respectively. When the first and second tag pins reach select locations within the respective first and second pin slots, the first cap screw is tightened into the first T-nut, and the second cap screw is tightened into the second T-nut, thereby securing the tag-pin within the tag engagement member.